Knife switch



Dec. 9, 1924.

B. E. GETCHELL KNIFE: SWITCH Filed July 8, 1922 INVENTOR BE. Gethe]1,

Patented Dec. 9, 1924.

UNITED STATES PATENT OFFICE.

BENJAMIN E. GETCHELL, OF PLAINVILLE, CONNECTICUT, ASSIGNOR TO THE TRUMBULL ELECTRIC MANUFACTURING COMPANY, OF PLAINVILLE, CONNECTICUT, A COR- PORATION OF CONNECTICUT.

Application filed July 8,

To all whom it may concern-.-

Be it known that I, BENJAMIN E. GE'roH- ELL, a citizen of the United States of America, residing at Plainville, Connecticut, have invented a new and useful Knife Switch, of which the following is a specification.

My invention relates to electric switches, particularly to those of the knife blade type having two or more pivoted contact arms or blades.

The main object is to provide a simple, inexpensive, but satisfactory means of securing the insulating cross bar to the blades.

Another object is to provide means of connection which shall be reliable but which will not require the use of projecting parts.

In its preferred form the invention contemplates the use of an insulating cross bar held in notches in the blades by means of integral lugs or shoulders formed from the material of the blade. Additional security and uniformity may be provided by providing the cross bar with grooves adapted to receive the blades at the proper points.

Figure 1 is a perspective view illustrating two switch blades with a cross bar which is sectioned at the point of connection with one blade.

Fig. 2 is a side view of a blade showing in cross sections a modified cross bar.

Fig. 3 is a side view of a blade before attaching the cross bar.

Fig. 4 is a perspective view of a grooved cross bar.

Figs. 5 and 6 are views similar to Fig. 2, but showing modified details of construction.

Fig. 7 is a perspective view of a modification in which the cross bar is seated in the notch flush with the edge of the blade.

The switch may have any number of blades such as 10 and 11 connected by a cross bar 12 formed of insulating material such as fiber.

Each blade is provided with a notch 13 adapted to receive one or more edges of a cross bar. These blades are usually formed of copper which is rather soft and therefore readily bent or de-formed.

The cross bar is preferably provided with recesses 14, 14 as shown in Fig. 4. These recesses may be drilled partly or entirely KNIFE SWITCH.

1922. Serial No. 573,585.

through the cross bar or may be punched in from the opposite sides of the bar.

The cross bar may be provided with grooves :24, 24 to receive the edges of the blades to more accurately space the blades when so required.

In order to secure the cross bar to the blades, lugs are formed at the corners of the notches 13 which are indented or pressed into the edges of the cross bar so as to grip the same securely. These lugs may be formed in various different ways, for instance, the lugs 15, 15 shown in Figs. 1 and 2 are formed by staking or notching the edges of the blade as at 16 and 17 and which operation also bends over the lugs.

In the forms shown in Figs. 1, 4, 5 and 6, the cross bar is preferably provided with recesses such as 14% to receive the tips of the lugs 15, 15, etc. as it is found in practice that the metal of the blade can be more readily forced into the material of the cross bar if some means is provided for relieving the strain on the tips of the lugs and the metal is then also forced into approximate conformation with the shape of the pre-formed recesses and thus more accurately and positively secure the parts together.

In the form shown in Fig. 2 a. transverse hole or passage 18 is formed in the cross bar, and the outer ends of this passage receive the tips of the lugs 15, 15.

In the form shown in Fig. 5, the lug 19 projects into a recess in one edge of the cross bar 20 and the lug 21 is formed by staking the edge of the blade as in Figs. 1 and 2.

In the form shown in Fig. 6 the lugs 22 and 28 are formed by simply compressing the metal of the blade adjacent the cross bar.

In the form shown in Fig. 7, the top of the cross bar is flush with the top edge of the blade which is an advantage in some instances. In this form it is not necessary to provide pie-formed recesses to receive the tips of the lugs 1515.

It is obvious that it is not necessary to actually sever the lugs 15, 15 from the body of the blade as the edge of a notch may be forced into angular engagement with the cross bar without cutting entirely through the metal of the blade.

It will be seen that this method of" attachment of the cross bar to the blades does not require any screws, nuts, or projections, and that the insulating cross bar serves not only as means for attaching a handle for operating the blades but it also still'ens the blades and holds them in their proper rela tive positions.

I claim:

1. In a knife blade switch, two or more blades having positioning notches, a cross bar seated in said notches, each blade having lugs at the opposite edges oi? its notches angiilarly embedded in the opposite edges oi said cross bar.

2. In knife blade switch, two or more blades having open notches, an insulating cross bar having shallow grooves with their walls interlocked with the walls of said notches, the metal at the edges oi s-aid notches being embedded in the edges of said cross bar.

3. In a knife blade switch, a switch blade having a notch in one of its edges, and an insulating cross-bar seated in said notch with the metal of the blade adjacent the opposite sides of said notch forced into the material of the cross-bar to retain the said cross bar in position;

4. In a knife blade switch, a. switch. blade having a notch in one of its longitudinal edges, and an insulating cross-bar seated in said notch. with the metal of the blade at the side of the notch displaced laterally and forcedinto the edge of saidcross-bar' to secure the cross-barvv inposition on the blade,

5. in a knife blade switch, a switch blade having anotch and a cross-bar of fihroiis insulating materiali seated in said notch, the metal of the blade adjacent said notch being displaced and forced angularly into the material of the body of said cross bar to secure the cross-bar to the blade.

BENJAMIN E. GETCHELL. 

